Pull tracing updates from Steven Rostedt:
"The major changes in this tracing update includes:
- Removal of non-DYNAMIC_FTRACE from 32bit x86
- Removal of mcount support from x86
- Emulating a call from int3 on x86_64, fixes live kernel patching
- Consolidated Tracing Error logs file
Minor updates:
- Removal of klp_check_compiler_support()
- kdb ftrace dumping output changes
- Accessing and creating ftrace instances from inside the kernel
- Clean up of #define if macro
- Introduction of TRACE_EVENT_NOP() to disable trace events based on
config options
And other minor fixes and clean ups"
* tag 'trace-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits)
x86: Hide the int3_emulate_call/jmp functions from UML
livepatch: Remove klp_check_compiler_support()
ftrace/x86: Remove mcount support
ftrace/x86_32: Remove support for non DYNAMIC_FTRACE
tracing: Simplify "if" macro code
tracing: Fix documentation about disabling options using trace_options
tracing: Replace kzalloc with kcalloc
tracing: Fix partial reading of trace event's id file
tracing: Allow RCU to run between postponed startup tests
tracing: Fix white space issues in parse_pred() function
tracing: Eliminate const char[] auto variables
ring-buffer: Fix mispelling of Calculate
tracing: probeevent: Fix to make the type of $comm string
tracing: probeevent: Do not accumulate on ret variable
tracing: uprobes: Re-enable $comm support for uprobe events
ftrace/x86_64: Emulate call function while updating in breakpoint handler
x86_64: Allow breakpoints to emulate call instructions
x86_64: Add gap to int3 to allow for call emulation
tracing: kdb: Allow ftdump to skip all but the last few entries
tracing: Add trace_total_entries() / trace_total_entries_cpu()
...
Automatic const char[] variables cause unnecessary code
generation. For example, the this_mod variable leads to
3f04: 48 b8 5f 5f 74 68 69 73 5f 6d movabs $0x6d5f736968745f5f,%rax # __this_m
3f0e: 4c 8d 44 24 02 lea 0x2(%rsp),%r8
3f13: 48 8d 7c 24 10 lea 0x10(%rsp),%rdi
3f18: 48 89 44 24 02 mov %rax,0x2(%rsp)
3f1d: 4c 89 e9 mov %r13,%rcx
3f20: b8 65 00 00 00 mov $0x65,%eax # e
3f25: 48 c7 c2 00 00 00 00 mov $0x0,%rdx
3f28: R_X86_64_32S .rodata.str1.1+0x18d
3f2c: be 48 00 00 00 mov $0x48,%esi
3f31: c7 44 24 0a 6f 64 75 6c movl $0x6c75646f,0xa(%rsp) # odul
3f39: 66 89 44 24 0e mov %ax,0xe(%rsp)
i.e., the string gets built on the stack at runtime. Similar code can be
found for the other instances I'm replacing here. Putting the string
in .rodata reduces the combined .text+.rodata size and saves time and
stack space at runtime.
The simplest fix, and what I've done for the this_mod case, is to just
make the variable static.
However, for the "<faulted>" case where the same string is used twice,
that prevents the linker from merging those two literals, so instead use
a macro - that also keeps the two instances automatically in
sync (instead of only the compile-time strlen expression).
Finally, for the two runs of spaces, it turns out that the "build
these strings on the stack" is not the worst part of what gcc does -
it turns print_func_help_header_irq() into "if (tgid) { /*
print_event_info + five seq_printf calls */ } else { /* print
event_info + another five seq_printf */}". Taking inspiration from a
suggestion from Al Viro, use %.*s to make snprintf either stop after
the first two spaces or print the whole string. As a bonus, the
seq_printfs now fit on single lines (at least, they are not longer
than the existing ones in the function just above), making it easier
to see that the ascii art lines up.
x86-64 defconfig + CONFIG_FUNCTION_TRACER:
$ scripts/stackdelta /tmp/stackusage.{0,1}
./kernel/trace/ftrace.c ftrace_mod_callback 152 136 -16
./kernel/trace/trace.c trace_default_header 56 32 -24
./kernel/trace/trace.c tracing_mark_raw_write 96 72 -24
./kernel/trace/trace.c tracing_mark_write 104 80 -24
bloat-o-meter
add/remove: 1/0 grow/shrink: 0/4 up/down: 14/-375 (-361)
Function old new delta
this_mod - 14 +14
ftrace_mod_callback 577 542 -35
tracing_mark_raw_write 444 374 -70
tracing_mark_write 616 540 -76
trace_default_header 600 406 -194
Link: http://lkml.kernel.org/r/20190320081757.6037-1-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Mark ftrace mcount handler functions nokprobe since probing on these functions with kretprobe pushes return address incorrectly on kretprobe shadow stack. Reported-by: Francis Deslauriers <francis.deslauriers@efficios.com> Tested-by: Andrea Righi <righi.andrea@gmail.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/155094062044.6137.6419622920568680640.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
The function_graph tracer has a stub function and its ops flag has the FTRACE_OPS_FL_STUB set. As the function graph does not use the ftrace_ops->func pointer but instead is called by a separate part of the ftrace trampoline. The function_graph tracer still requires to pass in a ftrace_ops that may also hold the hash of the functions to call. But there's no reason to test that hash in the function tracing portion. Instead of testing to see if we should call the stub function, just test if the ops has FTRACE_OPS_FL_STUB set, and just skip it. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The ASSIGN_OPS_HASH() macro was moved to fgraph.c where it was used, but for some reason it wasn't removed from ftrace.c, as it is no longer referenced there. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Changed 0 --> NULL to avoid sparse warning Corrected spelling mistakes reported by checkpatch.pl Sparse warning below: sudo make C=2 CF=-D__CHECK_ENDIAN__ M=kernel/trace CHECK kernel/trace/ftrace.c kernel/trace/ftrace.c:3007:24: warning: Using plain integer as NULL pointer kernel/trace/ftrace.c:4758:37: warning: Using plain integer as NULL pointer Link: http://lkml.kernel.org/r/20190323183523.GA2244@hari-Inspiron-1545 Signed-off-by: Hariprasad Kelam <hariprasad.kelam@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Enabling of large number of functions by echoing in a large subset of the functions in available_filter_functions can take a very long time. The process requires testing all functions registered by the function tracer (which is in the 10s of thousands), and doing a kallsyms lookup to convert the ip address into a name, then comparing that name with the string passed in. When a function causes the function tracer to crash the system, a binary bisect of the available_filter_functions can be done to find the culprit. But this requires passing in half of the functions in available_filter_functions over and over again, which makes it basically a O(n^2) operation. With 40,000 functions, that ends up bing 1,600,000,000 opertions! And enabling this can take over 20 minutes. As a quick speed up, if a number is passed into one of the filter files, instead of doing a search, it just enables the function at the corresponding line of the available_filter_functions file. That is: # echo 50 > set_ftrace_filter # cat set_ftrace_filter x86_pmu_commit_txn # head -50 available_filter_functions | tail -1 x86_pmu_commit_txn This allows setting of half the available_filter_functions to take place in less than a second! # time seq 20000 > set_ftrace_filter real 0m0.042s user 0m0.005s sys 0m0.015s # wc -l set_ftrace_filter 20000 set_ftrace_filter Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pull tracing updates from Steven Rostedt: - Rework of the kprobe/uprobe and synthetic events to consolidate all the dynamic event code. This will make changes in the future easier. - Partial rewrite of the function graph tracing infrastructure. This will allow for multiple users of hooking onto functions to get the callback (return) of the function. This is the ground work for having kprobes and function graph tracer using one code base. - Clean up of the histogram code that will facilitate adding more features to the histograms in the future. - Addition of str_has_prefix() and a few use cases. There currently is a similar function strstart() that is used in a few places, but only returns a bool and not a length. These instances will be removed in the future to use str_has_prefix() instead. - A few other various clean ups as well. * tag 'trace-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (57 commits) tracing: Use the return of str_has_prefix() to remove open coded numbers tracing: Have the historgram use the result of str_has_prefix() for len of prefix tracing: Use str_has_prefix() instead of using fixed sizes tracing: Use str_has_prefix() helper for histogram code string.h: Add str_has_prefix() helper function tracing: Make function ‘ftrace_exports’ static tracing: Simplify printf'ing in seq_print_sym tracing: Avoid -Wformat-nonliteral warning tracing: Merge seq_print_sym_short() and seq_print_sym_offset() tracing: Add hist trigger comments for variable-related fields tracing: Remove hist trigger synth_var_refs tracing: Use hist trigger's var_ref array to destroy var_refs tracing: Remove open-coding of hist trigger var_ref management tracing: Use var_refs[] for hist trigger reference checking tracing: Change strlen to sizeof for hist trigger static strings tracing: Remove unnecessary hist trigger struct field tracing: Fix ftrace_graph_get_ret_stack() to use task and not current seq_buf: Use size_t for len in seq_buf_puts() seq_buf: Make seq_buf_puts() null-terminate the buffer arm64: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack ...
Pull RCU updates from Ingo Molnar:
"The biggest RCU changes in this cycle were:
- Convert RCU's BUG_ON() and similar calls to WARN_ON() and similar.
- Replace calls of RCU-bh and RCU-sched update-side functions to
their vanilla RCU counterparts. This series is a step towards
complete removal of the RCU-bh and RCU-sched update-side functions.
( Note that some of these conversions are going upstream via their
respective maintainers. )
- Documentation updates, including a number of flavor-consolidation
updates from Joel Fernandes.
- Miscellaneous fixes.
- Automate generation of the initrd filesystem used for rcutorture
testing.
- Convert spin_is_locked() assertions to instead use lockdep.
( Note that some of these conversions are going upstream via their
respective maintainers. )
- SRCU updates, especially including a fix from Dennis Krein for a
bag-on-head-class bug.
- RCU torture-test updates"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (112 commits)
rcutorture: Don't do busted forward-progress testing
rcutorture: Use 100ms buckets for forward-progress callback histograms
rcutorture: Recover from OOM during forward-progress tests
rcutorture: Print forward-progress test age upon failure
rcutorture: Print time since GP end upon forward-progress failure
rcutorture: Print histogram of CB invocation at OOM time
rcutorture: Print GP age upon forward-progress failure
rcu: Print per-CPU callback counts for forward-progress failures
rcu: Account for nocb-CPU callback counts in RCU CPU stall warnings
rcutorture: Dump grace-period diagnostics upon forward-progress OOM
rcutorture: Prepare for asynchronous access to rcu_fwd_startat
torture: Remove unnecessary "ret" variables
rcutorture: Affinity forward-progress test to avoid housekeeping CPUs
rcutorture: Break up too-long rcu_torture_fwd_prog() function
rcutorture: Remove cbflood facility
torture: Bring any extra CPUs online during kernel startup
rcutorture: Add call_rcu() flooding forward-progress tests
rcutorture/formal: Replace synchronize_sched() with synchronize_rcu()
tools/kernel.h: Replace synchronize_sched() with synchronize_rcu()
net/decnet: Replace rcu_barrier_bh() with rcu_barrier()
...
The following commands will cause a memory leak:
# cd /sys/kernel/tracing
# mkdir instances/foo
# echo schedule > instance/foo/set_ftrace_filter
# rmdir instances/foo
The reason is that the hashes that hold the filters to set_ftrace_filter and
set_ftrace_notrace are not freed if they contain any data on the instance
and the instance is removed.
Found by kmemleak detector.
Cc: stable@vger.kernel.org
Fixes: 591dffdade9f ("ftrace: Allow for function tracing instance to filter functions")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>